Echocardiographic Pulmonary–Left Atrial Ratio and Epicardial Adipose Tissue as Noninvasive Markers of Obstructive Sleep Apnea

Background Obstructive sleep apnea syndrome (OSAS) is linked to pulmonary hypertension and cardiovascular risk, yet simple echocardiographic indices related to cardiopulmonary hemodynamics and cardiometabolic burden are limited. We evaluated ePLAR and epicardial adipose tissue (EAT) thickness as complementary, noninvasive echocardiographic markers associated with OSAS presence and severity in newly diagnosed patients. Methods In this cross‐sectional study, 63 polysomnography‐confirmed OSAS patients and 63 controls with a similar distribution of age, sex, and major comorbidities underwent transthoracic echocardiography. OSAS severity was classified as mild, moderate, or severe. ePLAR (TRVmax/E/e′) and EAT were measured. Diagnostic performance was assessed by ROC analysis (apparent discrimination), and prediction models for severe OSAS were fitted using Firth penalized logistic regression with bootstrap optimism correction. Results OSAS patients had higher EAT (0.62 ± 0.11 vs. 0.53 ± 0.06 cm) and ePLAR (0.37 ± 0.09 vs. 0.23 ± 0.04 m/s) than controls (both p < 0.001). Within OSAS, both measures increased stepwise with severity ( p < 0.001). In internally validated models, adding ePLAR and/or EAT to age/sex/BMI improved discrimination for severe OSAS. Conclusions EPLAR and EAT were associated with OSAS presence and severity and showed good apparent discrimination for severe OSAS in this cohort; these findings are hypothesis‐generating and require external validation in clinically representative populations before any clinical implementation. Trial Registration This study was observational and cross‐sectional in design and was not registered in a clinical trial registry because it was not an interventional clinical trial.